equipment OEM<\/a> under one number, from a distributor under a second, and from a power-transmission supplier under a third. Three stock lines, three reorder points, three sets of safety stock, one part.<\/p>\n\n\n\nUn-kitted work.<\/strong> A BOM is what lets a planner kit a job before the crew arrives. With no equipment BOM, the technician diagnoses the failure, walks to the storeroom, searches by description, and either finds the part, finds something that will do, or orders it. The repair that should have taken two hours takes a shift, or a day, and the substitute that was fitted is now the thing nobody recorded.<\/p>\n\n\n\nCriticality you cannot calculate.<\/strong> Spare parts criticality is derived from the equipment the part protects. A part with no equipment link has no criticality, which means it cannot be given a sensible min\/max, cannot be protected as a critical spare, and cannot be released as excess. It sits in the middle, carried indefinitely because nobody can say whether it matters. The monthly finance report is a list of exactly these items.<\/p>\n\n\n\nDecisions made on the wrong list.<\/strong> The practitioner put the practical consequence simply: if the system can narrow an orphan part down to five candidate assets instead of a thousand, a planner can resolve it in minutes. Without that, the planner does not resolve it at all, and the part stays unassigned until it is written off or found by accident during a breakdown.<\/p>\n\n\n\nThe cost compounds across sites. The same manufacturer wants network-level visibility so a plant that is out of a seal can find one at a sister site before raising an emergency purchase. That only works if both plants link the seal to equipment under the same description. Orphan parts are invisible to that search.<\/p>\n\n\n\n
Why can\u2019t you rebuild the BOM from the OEM drawing alone?<\/h2>\n\n\n\n Because the OEM drawing tells you what the OEM calls the part, not what the part is. Equipment manufacturers make a large share of their margin on spares, so a filler manufacturer\u2019s parts list will show \u201cbearing, part ABC-1234\u201d and leave out that it is an SKF 6205 available from any bearing distributor. The practitioner we worked with called this the historical challenge of the food industry: getting OEMs to say who their component suppliers are is \u201creally, really, really hard,\u201d and it is deliberate.<\/p>\n\n\n\n
This has three consequences for anyone trying to build BOMs from drawings.<\/p>\n\n\n\n
The BOM inherits the OEM\u2019s part numbers.<\/strong> A BOM that lists ABC-1234 is correct, but it is only useful for ordering from that OEM. It does not tell the storeroom that the same bearing is already on the shelf under the distributor\u2019s number, so the plant buys it again at OEM pricing.<\/p>\n\n\n\nDuplicates are structural, not accidental.<\/strong> When one machine\u2019s BOM lists the OEM number and another machine\u2019s BOM lists the SKF number for the same bearing, the system sees two parts. Every attribute-level clean-up finds these. The manufacturer expects to find the identical component under the OEM, a second OEM, and the power-transmission supplier, and that is before counting sites.<\/p>\n\n\n\nSome parts are modified to make you dependent.<\/strong> A sprocket that started as an off-the-shelf Martin part gets a proprietary attachment machined on, and an easy-to-source component becomes one that \u201conly works if it comes from them\u201d at many times the price. The drawing will not tell you this either.<\/p>\n\n\n\nThe drawing also contains things that are not spares. An equipment frame, a guard, and a base plate: all appear on the engineering BOM because they are part of the building, and none should ever be stocked. The equipment OEM manual\u2019s recommended-spares list, usually two pages, is a better guide to what to stock than the drawing, but it is also written to sell spares, and it carries the same hidden-manufacturer problem.<\/p>\n\n\n\n
So, the drawing is one source. The practitioner\u2019s guidance was to cross-reference it against the manual\u2019s recommended spares, then against purchase history (where did we buy this, and did the invoice name the real manufacturer), and then to resolve the OEM-to-manufacturer link explicitly: ABC-1234 is SKF 6205. Once that link exists, the duplication disappears and the BOM becomes usable for sourcing, not just for ordering from the OEM.<\/p>\n\n\n\n
His other instruction was about structure. Everything extracted from a drawing or spec sheet should land in the same noun-modifier-attribute format the storeroom already uses for its material master, so that \u201cwe\u2019re not trying to program our brains to look at data in a different way.\u201d A BOM in a different format from the material master is a BOM nobody will maintain.<\/p>\n\n\n\n
Why can\u2019t you rebuild the BOM from work order history alone?<\/h2>\n\n\n\n Because the truth about what is fitted to a machine is in the work orders, but it is trapped in three places the standard CMMS export does not reach: the 40-character order header, the long text nobody reads, and the goods movements that record what was issued without saying why. Work order history is the best source for the as-maintained BOM. It is also the hardest to extract.<\/p>\n\n\n\n
The reliability engineer we worked with pulled the history for one filler. It had thousands of work orders against it, split across two equipment numbers for the same physical machine. The order description field is limited to 40 characters. Confirmations were thin because \u201csome of these guys didn\u2019t fill out a whole lot.\u201d The useful detail, which part was replaced with what, lived in long text that could only be read by clicking into each order and copying it out by hand. His estimate for doing that across the fleet was not a number he was willing to say out loud.<\/p>\n\n\n\n
Three specific problems arise.<\/p>\n\n\n\n
The header lies by omission.<\/strong> \u201cReplace bearing\u201d in 40 characters does not say which bearing, which position, or whether it was the BOM part or whatever was on the shelf. Planners manage this today by exporting to Excel and managing comments there, which the manufacturer\u2019s maintenance leader described as the only way to get anything out of the system.<\/p>\n\n\n\nNotification details do not always reach the work order.<\/strong> When a mechanic lists the parts needed on the notification, whether that carries over to the work order depends on configuration. In the manufacturer\u2019s ECC system, some fields do not transfer, so the information exists but not where anyone will look for it.<\/p>\n\n\n\nGoods movements record consumption, not fitment.<\/strong> The issue log shows that a radiation curtain was charged to a sealer. It fitted to the X-ray machine downstream. The movement is correct as a cost posting and wrong as a BOM entry. Reading goods movements into a BOM without a sanity check will attach parts to the wrong equipment, which is the problem you started with.<\/p>\n\n\n\nThe approach that worked was to read all three sources together for one equipment at a time, over three to four years of history, and reconcile them against the existing BOM. For four pieces of equipment, that reconciliation surfaced many unique materials that had been consumed on work orders and did not appear in the equipment\u2019s BOM. The reliability engineer\u2019s reaction was that this is routine: \u201cmany times we look at our equipment and the bill of materials, and it\u2019s not associated to that equipment.\u201d<\/p>\n\n\n\n
Not all belong on the BOM. The manufacturer wanted them split into consumables (glue, filters, small hardware) that are issued to the job but never stocked as equipment spares, and non-consumables that should be reviewed and added. That split is a judgment the system can propose and a planner should confirm which is the subject of the next two sections.<\/p>\n\n\n\n
Substitute or new standard? The BOM update rule most systems get wrong<\/h2>\n\n\n\n A part fitted on a work order is not automatically the part that belongs on the BOM. Any process that updates the BOM every time a different part is consumed will corrupt it faster than the original neglect did, because a large share of substitutions is made for availability, not preference. The right rule has two branches, and the person closing the work order must be able to pick one.<\/p>\n\n\n\n
The maintenance leader we worked with laid out both cases from experience.<\/p>\n\n\n\n
Branch one: substitute, keep the standard.<\/strong> The equipment BOM calls for filter A. Filter A is out of stock. The technician fits filter B, same form, fit and function. The BOM should not change. Filter A is still what the plant wants to order next time. The work order should record that B was fitted as a substitute, so the history is honest, but the standard stays A. His words: \u201cI wouldn\u2019t automatically update just based on a change, because we see a lot of parts substituted because of availability, but not what we want to do long term.\u201d<\/p>\n\n\n\nBranch two: upgrade, change the standard.<\/strong> The BOM calls for an INA mounted bearing. The technician fits a Dodge mounted bearing with the same dimensions and attributes, and it performs better in the application. Now the plant does want Dodge to be the standard going forward. The BOM should change, and the INA part should drop off it.<\/p>\n\n\n\nThe two cases look identical in the goods-movement log. A different part was issued against the equipment. The only way to tell them apart is to ask someone who knows, which is why the BOM update has to be a proposal with an approval, not an automatic writeback.<\/p>\n\n\n\n
This also settles a related question: what to do when a part is replaced with a different quantity. Two bearings instead of one may mean the second was a spare taken for convenience, or that the BOM quantity was wrong. Again, propose, do not assume.<\/p>\n\n\n\n
The practical design is a comparison report. For each piece of equipment, show the BOM as it stands against the BOM the work order history implies, highlights only the differences (nobody wants to re-read 176 unchanged lines), and cite the work order that caused each one. The planner approves the three changes that are real, rejects the one that was an availability substitution, and the system writes the approved version back. Versioning the BOM at each approved change gives the plant a history of the machine as maintained, from installation to today, which is something no CMMS provides out of the box.<\/p>\n\n\n\n
What does good equipment BOM rebuild look like in practice?<\/h2>\n\n\n\n A BOM rebuild that holds up is a reconciliation of four sources with one approval step, done equipment by equipment, in the same material format the storeroom already uses. Any single source produces a BOM that is confidently wrong. The four together produce a proposal a planner can sign off in minutes.<\/p>\n\n\n\nQuelle<\/strong><\/td>What it tells you<\/strong><\/td>What it gets wrong on its own<\/strong><\/td><\/tr><\/thead>OEM drawing or spec sheet<\/td> The as-built component list, with hierarchy (assembly, sub-assembly, part) and quantities<\/td> OEM part numbers only; include frames and guards that are not spares; no component manufacturer<\/td><\/tr> OEM manual, recommended spares<\/td> Which components the OEM expects you to stock, with suggested quantities<\/td> Written to sell OEM spares; same hidden-manufacturer problem; ignores your duty cycle<\/td><\/tr> Purchase history<\/td> Where you bought the part and, sometimes, the real manufacturer on the invoice<\/td> Reflects what procurement could get, not what the machine needs; multiple vendors for one part<\/td><\/tr> Work order and goods-movement history<\/td> What was fitted, when, and on which order<\/td> Substitutes look like standards; consumables look like spares; mischarged issues point at the wrong machine<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nThe sequence the manufacturer and we settled on:<\/p>\n\n\n\n
\nExtract the as-built BOM from the drawing<\/strong>, keeping the multi-level hierarchy so sub-assemblies are preserved, and flagging anything that is structural rather than a spare.<\/li>\n\n\n\nCross-reference the manual\u2019s recommended spares<\/strong> to separate what is on the drawing from what should be stocked.<\/li>\n\n\n\nResolve OEM part numbers to component manufacturers<\/strong> using purchase history, invoice detail and the plant\u2019s own enriched material master. ABC-1234 becomes SKF 6205, and the duplicate stock lines collapse into one.<\/li>\n\n\n\nReplay the work order history<\/strong> against the as-built BOM, one equipment at a time, to find parts consumed but not listed, and parts listed but never consumed.<\/li>\n\n\n\nPropose, do not write.<\/strong> Show only the differences, cite the work order behind each, split consumables from non-consumables, and let a planner approve, reject or mark as substitute.<\/li>\n\n\n\nVersion the result.<\/strong> Each approved change creates a new BOM version with a date and a reason, so the plant has an as-maintained history rather than a single overwritten list.<\/li>\n<\/ul>\n\n\n\nTwo rules sit over the whole process. First, every extracted record lands in the storeroom\u2019s existing noun-modifier-attribute format: component class first (bearing, motor, gearbox), then attributes. The maintenance leader\u2019s point was that as an end user deciding whether to stock something, \u201cI need to quickly know what this component is.\u201d Second, the planner\u2019s job shrinks to confirmation. If the system narrows an orphan part to five candidate assets, the planner can finish the monthly list. If it hands them a thousand, nothing happens.<\/p>\n\n\n\n
How MRO360 rebuilds and maintains equipment BOMs<\/h2>\n\n\n\n MRO360 treats BOM as the thing that connects every other inventory decision, so it rebuilds and maintains it from the four sources above rather than asking the plant to populate it by hand. The work that used to need an SME reading PDFs, and a planner clicking through two thousand work orders, runs as AI-native extraction and reconciliation with the planner kept for approval.<\/p>\n\n\n\n
\nDrawing and manual extraction.<\/strong> Upload a drawing, spec sheet or manual, or point MRO360 at the folder, and it returns the multi-level BOM with hierarchy, quantities, manufacturer and part numbers, in the same component-class-and-attribute structure as the material master. Scanned prints and PDFs are fine; the plant we worked with had paper drawings for older lines and most of its manuals as PDF.<\/li>\n\n\n\nOEM-to-manufacturer resolution.<\/strong> Where the drawing gives only the OEM\u2019s part number, MRO360 uses purchase history, invoice detail and the enriched material description to propose the component manufacturer and identify the equivalent already in stock. Duplicate stock lines for one bearing become one.<\/li>\n\n\n\nWork order replay.<\/strong> Work order headers, long text and goods movements are read together for each equipment and compared against the existing BOM. Parts consumed but not listed are surfaced with the work order that used them, split into consumables and non-consumables.<\/li>\n\n\n\nSubstitute-aware approval.<\/strong> Every proposed change arrives as a difference against the current BOM, with the originating work order, and the planner marks it as a substitute, a new standard or a rejection. Only the changes approved are written back, as a new BOM version.<\/li>\n\n\n\nOrphan part matching.<\/strong> For parts the system cannot connect to any equipment, MRO360 uses the part\u2019s attributes, purchase history and the work orders it was issued against to propose the handful of assets it most likely belongs to, so the monthly \u201cno BOM\u201d list becomes a review of five candidates instead of a search across a thousand.<\/li>\n\n\n\nOne view across systems.<\/strong> Because it reads from SAP PM, legacy CMMS exports and spreadsheets alike, it works during an S\/4HANA migration and across acquired plants that are not yet on the same system.<\/li>\n<\/ul>\n\n\n\nWhat it does not do is decide on the plant. The judgment calls, substitute versus standard, consumable versus spare, which equipment an orphan belongs to, stay with the people who know the equipment. The system removes the reading, the clicking and the searching, which is where the hours went.<\/p>\n\n\n\n
H\u00e4ufig gestellte Fragen<\/h2>\n\n\n\n What is the equipment BOM in maintenance?<\/strong> An equipment bill of materials is the list of spare parts and components that belong to a specific piece of equipment, held against the equipment record in the CMMS or EAM system. It is different from manufacturing BOM, which lists what goes into a product. A maintenance BOM lets planners kit work orders, link spares to criticality, and know what to stock for each asset.<\/p>\n\n\n\nWhat is the difference between an engineering BOM and a maintenance BOM?<\/strong> The engineering BOM is the OEM\u2019s as-built component list, including frames, guards and structural items that are never stocked. The maintenance BOM is the subset you would replace bearings, seals, belts, motors, sensors. Building the maintenance BOM straight from the engineering drawing without filtering produces a list full of items that should never be spares.<\/p>\n\n\n\nWhy are parts in my storeroom not linked to any equipment?<\/strong> Usually one of three reasons: the equipment BOM was never created, the part was bought under a different number from the one on the BOM (often an OEM number versus a manufacturer number), or the part was introduced by a work order that never updated the BOM. Acquired plants and sites on legacy CMMS systems tend to have all three.<\/p>\n\n\n\nHow do I find out which equipment an unlinked spare part belongs to?<\/strong> Use the data you already have purchase history (which supplier, which invoice, which cost center), work order and goods-movement history (which equipment it was issued against), and the part\u2019s attributes compared to parts that are linked. Done manually this takes hours per part. AI-native tooling can rank the likely equipment and leave the planner to confirm.<\/p>\n\n\n\nWhy don\u2019t OEM drawings give the real manufacturer part number?<\/strong> Because equipment OEMs earn a large share of their margin on spares. Listing an SKF or Dodge part number on the drawing would let you buy from a distributor. So, the drawing lists the OEM\u2019s own number. Some OEMs will share component sources; many will not. Purchase history and physical inspection are the usual routes to the real manufacturer.<\/p>\n\n\n\nWhat is an OEM part number cross reference?<\/strong> A cross reference maps the OEM\u2019s part number for a component to the component manufacturer\u2019s own number, for example OEM part ABC-1234 to SKF 6205. With the cross reference in the material master, the storeroom can see that it already stocks the part under another number, source it from alternative suppliers, and stop carrying the same bearing three times.<\/p>\n\n\n\nShould the BOM update automatically when a different part is used on a work order?<\/strong> No. Many parts are substituted because the standard part was out of stock, not because the plant wants to change the standard. The BOM should change only when the plant deliberately adopts a new part. Treat every work order consumption as a proposed change that a planner approves, rejects or records as a substitute.<\/p>\n\n\n\nHow do I rebuild equipment BOMs from work order history in SAP PM?<\/strong> Pull the order headers, the long text and the goods movements for one equipment at a time, over several years, and compare what was consumed against the existing BOM. Watch for three traps: the 40-character order description, notification fields that did not transfer to the order in your configuration, and goods movements charged to the wrong equipment. Review the differences rather than the whole list.<\/p>\n\n\n\nDo consumables belong to the equipment BOM?<\/strong> Generally, not. Glue, filters, small hardware and lubricants are issued to jobs but are not equipment-specific spares. When replaying work order history, separate consumables from non-consumables so the review focuses on components that should be stocked against the asset.<\/p>\n\n\n\nHow does equipment BOM accuracy affect spare parts criticality?<\/strong> Criticality is inherited from equipment. A part with no equipment link has no criticality, so it cannot be given a correct min\/max, protected as a critical spare, or released as excess. Fixing the BOM is the prerequisite for any criticality-based inventory policy.<\/p>\n\n\n\nCan AI build equipment BOMs from scanned drawings and PDFs?<\/strong> Yes. AI-native extraction reads drawings, spec sheets and manuals, including scans, and returns the multi-level BOM with hierarchy, quantities and part numbers. The remaining judgment, which items are spares, which manufacturer sits behind the OEM number, which equipment an orphan belongs to, is proposed by the system and confirmed by the planner. This is how MRO360 handles it.<\/p>\n\n\n\nFind out how many of your parts have no home<\/h2>\n\n\n\n Send us the monthly \u201cparts not on a BOM\u201d report, or an inventory extract, and we will show you how many of those items are duplicates of parts you already link, which equipment the rest most likely belong to, and what it would take to rebuild the BOMs for your top critical assets from the drawings and work order history you already have.<\/p>\n\n\n\n
Book a 30-minute BOM assessment.<\/a><\/strong> Bring one equipment\u2019s work order history and its drawing; we bring the reconciliation.<\/p>\n\n\n\n<\/p>","protected":false},"excerpt":{"rendered":"
An equipment bill of materials (equipment BOM) is the list of spare parts that belong to a specific asset: the bearings, seals, motors, belts and valves a technician will need when that machine fails or is rebuilt. In most plants the BOM in the CMMS is wrong, incomplete or missing. The result is a storeroom […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[64],"tags":[113],"class_list":["post-47196","post","type-post","status-publish","format-standard","hentry","category-blog","tag-mro"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/posts\/47196","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/comments?post=47196"}],"version-history":[{"count":1,"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/posts\/47196\/revisions"}],"predecessor-version":[{"id":47198,"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/posts\/47196\/revisions\/47198"}],"wp:attachment":[{"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/media?parent=47196"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/categories?post=47196"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.verdantis.com\/de\/wp-json\/wp\/v2\/tags?post=47196"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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